Americans leave behind countless digital footprints from everyday activities like making a phone call or using a credit card--footprints government agencies regularly track as part of their counterterrorism efforts.

The collection, retention, and dissemination of this information has dangerously escaped public oversight and congressional scrutiny, public sector experts warned Congress on Wednesday. If the next Congress and administration do not take steps to rein in these programs that are bloating the federal government, they said, it will come at the expense of both civil liberties and national security.

Policy experts laid out their concerns to the House Homeland Security Committee on Wednesday, which hosted a series of roundtable discussions on privacy and civil liberties. Too many loopholes exist in the Privacy Act, government data mining programs are ineffective, and information-sharing programs are growing without any accountability, they said.

"The truth is, we cannot do everything, so we have to set priorities that maintain the values of a free society," said Laura Murphy, president of Laura Murphy & Associates.

It is well founded that the government runs data-mining programs through which they monitor some people's activities in search of unusual information that may indicate terrorist activity is at work. However, there is "massive overclassification" of such national security programs, said Michael German, national security policy counsel for the American Civil Liberties Union.

The Homeland Security Committee should take more steps to hold data-mining programs publicly accountable, panelists said, particularly predictive data-mining programs, which aim to predict terrorist activity based on previously established patterns.

The federal government has been too secretive about predictive data mining, said Fred Cate, director of the Center for Applied Cybersecurity Research at Indiana University, because "the lesson from the (Total Information Awareness) debacle is just don't say what you're doing, and you won't get the pushback."

There would be pushback, panelists said, because there is zero evidence predictive data mining has ever or would ever be effective for combating terrorism.

"Predictive data mining is akin to alchemy or astrology in its relationship to science," said Tim Sparapani, senior legislative counsel for the ACLU.

Sparapani said the committee should do everything in its power to enact legislation explicitly shutting down predictive data mining.

Not only are these programs ineffective, but there are few legal limits to how information can be used once it is collected, breeding in people "a fundamental distrust and contempt" of the government, Cate said.

There should also be statutory limitations to how long such information can be retained, the panelists said.

"Enormous quantities of data are being acquired," Sparapani said. "We know all it does is create noise in the system."

Protections of the Fourth Amendment
There is also the danger that, as counterterrorism programs solicit more and more help from traditional law enforcement, the protections of the Fourth Amendment will be encroached upon. The Fourth Amendment has already "been rendered a paper tiger in the area of data mining," Cate said.

Increasingly, Murphy said, the Homeland Security Department refers to the goals of preventing crime and preventing terrorism interchangeably when providing guidance to its "fusion centers" across the country, where state and local law enforcement share intelligence with federal agencies.

About 60 fusion centers have been established in a number of states--without proper congressional oversight, German said.

"I would ask the committee to recognize demanding accountability from law enforcement agencies is essential to our security," he said, emphasizing the need for metrics. "If we can't measure how effective these programs are, then we shouldn't fund them."

Panelists also urged the Homeland Security Committee to hold a hearing to review the Information Sharing Environment, which Congress established in 2004 in response to the terrorist attacks of September 11, 2001. President Bush issued privacy guidelines for the ISE in 2006, but they are insufficient, they said.

"The ISE was enacted without any hearings on the civil liberties aspects on its creation," said Kate Martin, the director for the Center for National Security Studies. "If we're no longer going to have a government limited in how much information it collects, it should be limited in what it can share."